Thanks @maton00 to take my defence 🙂 : it looks like many of these answers are solely driven by the jealousy of some improvised tribunes... 😀
@6A3sUMMER : thanks - and be sure that I never made all your calculations 😱 ! But nonetheless, I'm pleased to see that you draw the conclusion that my simple design works as it should (since 2008 for the final build, and wooden prototype was tested since 2003).
The distortion values I measured were obtained with SpectraLAB real-time analyser and generator. The harmonic decay is regular, with even harmonics dominants. Since I could reinstall that software, I should be able to retrieve the matching files - well, I hope so ! 😱
Maybe there's a misunderstanding about the term "Ultimate" : I wanted a simple circuit, showing correct and reliable performance, constant with time passing by, along with a Retro-Cool look and compactness (chassis dimensions : 275x175x66mm). Those expectations are met - at least for me - hence the name. Ultimate means ultimate - not perfect, OK ? 😉
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@6A3sUMMER : thanks - and be sure that I never made all your calculations 😱 ! But nonetheless, I'm pleased to see that you draw the conclusion that my simple design works as it should (since 2008 for the final build, and wooden prototype was tested since 2003).
The distortion values I measured were obtained with SpectraLAB real-time analyser and generator. The harmonic decay is regular, with even harmonics dominants. Since I could reinstall that software, I should be able to retrieve the matching files - well, I hope so ! 😱
Maybe there's a misunderstanding about the term "Ultimate" : I wanted a simple circuit, showing correct and reliable performance, constant with time passing by, along with a Retro-Cool look and compactness (chassis dimensions : 275x175x66mm). Those expectations are met - at least for me - hence the name. Ultimate means ultimate - not perfect, OK ? 😉
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When "ultimate" for you means "simple, correct, reliable and not perfect", well OK.
However, with the two noval sockets you already have, and replacing one of your 12AX7's with a 5687 or 12B4, you can turn this amplifier into a better measuring and sounding one.
Just my two cents (no jealousy involved).
However, with the two noval sockets you already have, and replacing one of your 12AX7's with a 5687 or 12B4, you can turn this amplifier into a better measuring and sounding one.
Just my two cents (no jealousy involved).
C'est ça, ouais ! Gaudrioles, Billevesées, Balivernes, Sottises, Calembredaines, Carabistouilles... 😀😀😀
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In many SE 300B amplifiers builds the output transformer and first tube driver stage are not ultimate 😉
Yes. And I also think that there's a number of guys here which are not ultimate in their minds... 😉
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I am tired of these kind of so-called "experts" who know everything without ever having learned anything, these "kings" of the simulator who are afraid of a soldering iron, these "gurus" who have an opinion on everything but above all an opinion, these "audiophiles" who heard everything and never listened to anything ... 🙄
And most of all : how many of them have already taken a copy of my circuit - beside proof-less, free denigration ? Sait-on jamais, des fois qu'y marcherait bien... 😀
Merci, au revoir.
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Wow! You seem to think that you are the only one here using a soldering iron and the only one with experience building SE tube amps....
Please stick to English! This is not a French forum.
Please stick to English! This is not a French forum.
It would be great to run some real world tests on these circuits. Isn't the 300b a relatively easy tube to drive? WE used the 310a pentode and it shows 5mA as an operating point.
Yes, it's easy compared to 845 biased at -150V.
But IME the 300B responds well to a generous driver design, as well as measures to avoid blocking distortion (avoid RC coupling to the grid).
It may require more than the usual spectrum plot to at 1kHz stimulus to see the nuances.
But IME the 300B responds well to a generous driver design, as well as measures to avoid blocking distortion (avoid RC coupling to the grid).
It may require more than the usual spectrum plot to at 1kHz stimulus to see the nuances.
Those WE 91 amps were considered "economical" (low voltages, no ITs) even back then, and the audio standards had changed a bit over the last 90 years.
It's quite a mediocre amp - low power (just over a half of what 300B is capable of in A1), poor frequency response (at HF - due to the very high impedance driver) and very harsh overloading (again due to the driver).
Not the thing that should be used as the reference in 2020.
It's quite a mediocre amp - low power (just over a half of what 300B is capable of in A1), poor frequency response (at HF - due to the very high impedance driver) and very harsh overloading (again due to the driver).
Not the thing that should be used as the reference in 2020.
Naturally, WE staff knew how to drive their valve.
But that does not mean that their amplifier design goals have to be ours, in our time and place.
But that does not mean that their amplifier design goals have to be ours, in our time and place.
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I remember enjoying this article many years ago
https://www.pearl-hifi.com/06_Lit_A...apers/Loesch_Thorsten/Thorsten_on_SE_Amps.pdf
https://www.pearl-hifi.com/06_Lit_A...apers/Loesch_Thorsten/Thorsten_on_SE_Amps.pdf
Mercy, your circuit is just second best. But I don't have to listen to a mediocre amp. I can listen to real beefy driver stages in a SET amp. No puny stages.
Klangfilm themself thought that puny drivers are enough. But they were mostly after low distortion amps. Maybe the WE engineers too had those design goals in mind when they designed the model 91?
Btw, If you cannot describe in english, use google translate and write in french.
But you can't expect anyone here to understand french language that is only practised in small parts of the world.
Klangfilm themself thought that puny drivers are enough. But they were mostly after low distortion amps. Maybe the WE engineers too had those design goals in mind when they designed the model 91?
Btw, If you cannot describe in english, use google translate and write in french.
But you can't expect anyone here to understand french language that is only practised in small parts of the world.
Yes cause audio and tubes are synonyms of arthritis, tinnitus and big egos 😀
Please stop making absurd comments if its to dennigrate this isnt the place, but then we yet to know your remarkable abilities to design something, perhaps what is known is your ability to dennigrate and destroy, if you don't have something good to say please don't, then you can have time to comfortably hear Wagner inside a cave with your out or this world engineering skills 😡
Please stop making absurd comments if its to dennigrate this isnt the place, but then we yet to know your remarkable abilities to design something, perhaps what is known is your ability to dennigrate and destroy, if you don't have something good to say please don't, then you can have time to comfortably hear Wagner inside a cave with your out or this world engineering skills 😡